Wall-to-wall carpeting is usually installed with an underlay or padding to provide comfortable walking. It is somewhat difficult to install such carpeting over a normal underlay because of the need to stretch the carpeting toward the wall over an underlay that tends to cling to the carpeting. This causes uneveness in the underlay and the carpeting. Contrary to other carpet and underlay structures, in this instance it would be desirable for the face of the underlay which contacts the carpeting to be of low friction so the carpet can slide easily over the underlay during installation. Relative sliding after installation is not a problem since both the carpeting and the underlay are fixed around the entire perimeter.
The general structure of the overlay described in my U.S. Pat. Nos. 4,504,537 and 4,504,538 is admirably suited for the purposes of the present invention except for the central stiffening lattice and the upper layer which contacts the carpeting. My copending application Ser. No. 912,982 filed Sept. 29, 1986 now U.S. Pat. No. 4,668,559 discloses an underlay for wall-to-wall carpeting with a central layer of fiber batting, a lower outer layer of heat fused fibers in a corrugated pattern, and an upper outer layer of a low friction spun woven polyester scrim. While this product is quite satisfactory in many applications, the layer of scrim is somewhat fragile and does not resist rough handling as well as it should.
It is an object of this invention to provide an improved rug underlay having characteristics suitable for use with wall-to-wall carpeting. It is another object of this invention to provide a rug underlay of fibrous material having a uniform consistence, no unpleasant odor, and a clean appearance. It is still another object of this invention to provide a rug underlay having a carpet contacting surface that is abrasion-resistant has low friction and will permit carpeting to slide over it easily. Still other objects will be apparent from a more detailed description of this invention which follows.